The history of the Putnam Division goes back to 1869, when the New York & Boston was chartered to build a new railroad from High Bridge in the Bronx to Brewster in Putnam County. The route would go through several name changes and reorganizations before actual construction began. At first, the New York & Boston was to be part of a plan to connect Boston with the Erie Railroad. Those plans collapsed and in 1873 the line was reorganized as the New York, Boston & Montreal. The New York & Boston was to be just one link in a new trunk line to Canada. The Panic of 1873 wiped out the grandiose plans, and the investors reorganized as the New York, Westchester & Putnam in 1877. The reorganized line was leased to the New York City & Northern, later becoming the New York & Northern in 1878, and construction finally began. The line was completed in 1880, and regular service began in 1881. A connection was made with the New York & Harlem at Brewster for service to the north, and with the New York & New England for Boston. The New York & Northern terminated at 155th Street in Manhattan, where direct connections were made with the Ninth Avenue Elevated. The Mahopac Falls Railroad was built from Baldwin Place north to the Mahopac iron mines in 1884. In 1888, the Yonkers Rapid Transit branch to Getty Square was built over the right of way of the West Side & Yonkers. By the 1890s, the NY&N had lost a lot of traffic and its outside connections once the NY&NE coming under the control of the New Haven. Afraid that a competing company would purchase the line and try to start a rate war with either the New York Central or the New Haven, financier J.P. Morgan purchased the failing NY&N at a bankruptcy auction in 1894 and reorganized it as the New York & Putnam. He then leased the NY&P to the New York Central, operating it as their Putnam Division. In 1913, the NY&P was formally merged into the New York Central.

During New York Central control, many changes took place. In 1902, the branch to Mahopac Mines was cut back to Mahopac Falls. That same year, a mile-long spur was built from Yorktown Hieghts to serve the proposed site of the Mohansic State Hospital. In 1915, New York City objected to the threat of water pollution to the Croton Reservoir from this project. The branch was abandoned in 1917. In 1916, NYC moved the Put’s terminal from 155th Street to Sedgwick Avenue (just south of High Bridge). The swing bridge over the Harlem River was sold to the IRT subway, connecting with their new Jerome Avenue line. In 1926, the Putnam Division was electrified with third rail from Sedgwick Avenue up to Van Cortlandt Junction, and the entire Getty Square Branch.

John D. Rockefeller was annoyed by the railroad that ran through his family’s estate in Pocantico Hills. Rockefeller approached the railroad with a plan to move the line off his property. On April 15, 1930, a construction crew of 500 men began work on the railroad relocation. Three stations were closed: Tarrytown Heights, Tower Hill, and Pocantico Hills. The new route opened in 1931. It served fewer people and generated no freight traffic. That same year the Mahopac Falls branch was abandoned. At the end of 1943, the New York Central filed for abandonment of the Getty Square branch. After a lengthy court battle, the Federal government ordered the line to be scrapped in December 1944.

In 1956, the New York Central announced its intention to end all commuter service on the Putnam Division, and increase fares on the nearby Harlem and Hudson Divisions. By 1957 the number of trains was cut in half. The reduced service led to even lower ridership and the railroad went back to the commission with another petition to end service later that year. In March 1958, the commission approved the railroad’s petition, and the last Putnam Division passenger train ran on May 29. An interdivisional shuttled operated by Harlem Division crews continued until 1959.

Because the line had no tunnels and good clearances, “high and wide” freight loads kept the Putnam Division busy until the West Shore was upgraded to accept oversize freight traffic in the early 1960s. In 1962, trackage abandonment began in earnest. First to go was the 23 miles between East View and Lake Mahopac. More tracks were removed and service declined through the Penn Central and Conrail eras. Today, the entire line has been lifted, and much of the right-of-way has been converted to recreational trail use.